1. Field of the Invention
The present invention concerns a paper holder having a locking device for preventing clipping fingers from incidental opening.
2. Description of the Prior Art
In a paper holder, arcuate clipping fingers that conduct closing movement to form a semi-circular shape are opened, typically, by turning a manipulation member disposed to a longitudinal end of the paper holder or by the action of inverting the warp of a main body on which the clipping fingers are planted. Anyway, the clipping finger can be closed or opened by applying a closing/opening operation as required.
Generally, a paper holder basically has such a constitution as capable of retaining each of the states of the clipping fingers, namely, an open state and a closed state once attained by an operation given to them till a next operation is applied in the opposite way.
Compression stresses exert on the main body having the clipping fingers planted thereon when both sides of the main body are seized between a back plate, and this produces warping force of deforming them into arcuate cross sectional shapes. This results in bistable forms opposite to each other, that is, either an convex or concave shape.
In most of paper holders in the prior art, when it is intended to close the clipping fingers into a semi-circular shape, paired clipping fingers are closed to join the top ends of them by externally urging the outer circumferential ends of them.
However, even when the clipping fingers are once put into the closed state, they are sometimes caused to open spontaneously by external pressure, impact shock or the like, thereby detaching engaged sheets of paper out of the clipping fingers to trouble a user. This incidental or unwilling opening of the clipping fingers are often caused in the course of marketing communication before goods are handed to end users.
As an example, such troubles occur most frequently at the inside of a packaging case containing a plurality of paper holders, in particular, during transportation of them with the page-opening side of the paper holders being turned downward.
The size of sheets of paper engaged in a paper holder is generally smaller than that of a paper holder cover and all the weight of the engaged sheets of paper are supported only by the holder cover on both outer sides when the paper holder turned downward.
If packaged paper holders are fallen even from a slight height, weight of the engaged sheets of paper is exerted all together on the clipping fingers by the shock upon collision, which makes the clipping fingers open and all the engaged sheets of paper are detached from the paper holder.
Once after the sheets of paper have been detached, they are scattered at a time when the paper holders are taken out of the package, to worsen their commercial value.